Thank you for posting in the Community. Allow me to help share some insight about the logo size change when printing invoice.
Currently, there are reports about logos not showing the correct size when printing sales forms in QuickBooks Online. Our engineering team is aware and working to get this resolved.
As a workaround, you can change the logo format from .jpg to .gif, then upload it to QuickBooks. Please make sure to use Save as to create a new copy of the logo, so you don't overwrite the original file. Let me guide you how:
At the top right, select the Gear icon.
Choose Custom Form Styles.
On the form, you wish to customize, click Edit in the ACTION column.
Under the Design tab, select Make logo edits.
Select the + sign to open the Logo gallery.
Click the + then locate and open the file.
Choose your desired logo then Save as.
I've added some links below for additional reference while working with QuickBooks:
I also suggest calling our Customer Care Support to add your company details to the affected users' list. This will also sign you up to receive email updates as soon as they become available.
That should point you in the right direction today. Please know that I'm just a post away if you have any other questions about logos or about QuickBooks Online. I'll be happy to help you further. Wishing you and your business continued success.